Gravitude DepthWatch: seafloor subsidence monitoring

Production of hydrocarbons from offshore reservoirs often leads to subsidence of the seafloor. The measurement of how this subsidence distributes laterally is a powerfull geophysical tool for understanding the dynamics of the reservoir.

Gravitude DepthWatch surveying technology provides unique field-wide subsidence measurements with an accuracy of a few millimeters.

Pressure depletion caused by hydrocarbon production induces compaction of the reservoir, which is partially propagated to the surface and causes seafloor subsidence.

The Ormen Lange field case

Ormen Lange is the second largest gas field in Norway.

Back in 2012, installing compression facilities and drilling infill wells were considered as options to increase gass recovery at Ormen Lange. Two uncertainties needed to be addressed to decide on the optimal strategy, namely water break-through and compartmentalization.

A set of feasibility including seismic and electromagnetic methods concluded that monitoring 4D gravity and seafloor subsidence would provide the required answers in the most timely manner.